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Fishery Bulletin 88(4), 1990 



Chi-square analyses 



Contingency chi-square analyses were performed 

 between the two newly sampled collections at each of 

 the polymorphic loci. Because of their low frequencies, 

 all variant alleles at each locus were pooled into one 

 class. Significant heterogeneity between Necker Island 

 and Maro Reef was observed for E»tS (/- = 5.61, df 

 = 1, P<0.020). 



Contingency chi-square analyses were also per- 

 formed between the data gathered in this study and 

 those of Shaklee and Samollow (1984) at each of the 

 polymorphic loci. Significant heterogeneity was ob- 

 served between the Necker Island 1987 and 1979-80 

 collections at E^tS (x" = 5.86, df = 1, P<0.025). 



Shaklee and Samollow (1984) reported fluctuating 

 frequencies over years at the EstD locus and concluded 

 that the 1980 samples represented a cohort with an 

 unusual frequency. Therefore, we tested for hetero- 

 geneity between our data and the 1979 and 1980 EstD 

 data separately. Both Maro Reef and Necker Island 

 were significantly different for the 1980 comparison 

 (Maro Reef, r = 9.71, df = 1, P< 0.005; Necker Island, 

 X- = 15.42, df = 1, P<0.001). The Necker Island 1987 

 data were significantly different from the 1979 data 

 (r = 6.10, df = 1, P<d.02): the Maro Reef data were 

 not significantly different. 



Number of allelic classes 



The total number of observed alleles at all sampled loci 

 can also be used as an indicator of overall variability. 

 Shaklee and Samollow (1984) observed a total of 18 dif- 

 ferent allelic classes in both the Maro Reef and Necker 

 Island collections; we observed, for the same loci, 16 

 and 15 classes, respectively (Table 1). Although three 

 classes (with frequencies of 0.010 or less) detected 

 earlier were not observed in this study, two new alleles 

 were observed. 



It is also important to note the persistence of low- 

 frequency allelic classes. Gpi(^). Pgiti(J), and Pgm(s) 

 were present in the 1978-80 Maro Reef collections at 

 frequencies of 0.009 or less; all were present in the 1987 

 collection. Gpi{s) and Mpiij) were present in the 

 1978-80 Necker Island collection at frequencies of 

 0.007 or less; both were present in the 1987 collection. 



Heterozygosity 



Heterozygosities were calculated for each locus for 

 each population (Table 2). The EstS heterozygosities in 

 the 1987 Necker Island collection were lower than 

 those observed in the Hawaiian Archipelago during 

 1978-80 as no variants at this locus were observed. 

 However, the 1987 Necker Island average heterozy- 

 gosity over all loci was 0.023 (assuming monomorphism 

 for the 39 additional loci previously resolved) compared 

 with the value of 0.021 reported in the earlier study. 

 Mean heterozygosities were statistically indistinguish- 

 able l»etween the two populations and those observed 

 in the earlier study. It should be noted, though, that 

 differences on the order of 5% heterozygosities may 

 require that large numbers of loci be screened to 

 statistically test significant differences, and tests of 

 heterozygosities are particularly insensitive when com- 

 j)aring low levels of heterozygosity such as observed 

 in this study (Archie 1985). 



Discussion 



Stability of allele frequencies over at least 7 years was 

 found at Gpi, Mpi. Pgm, Tpepl, and Tpe}i2. The gene 

 frequencies of spiny lobster from Maro Reef and 

 Necker Island appear to be stable both l.ietween col- 

 lection sites and between years at all loci, with the 

 exception of the two esterase loci. The variability at 



